As the time progresses, the Internet and the mobile communication network have provided huge amounts of function applications. The users can not only use the traditional applications on the mobile terminals, for example, answering or making calls with smart phones; at the same time, the users can also browse the web pages, transmit pictures, play games and the like on the mobile terminals.
Along with the more frequent using of the mobile terminals, these mobile terminals need to be charged frequently. In addition, along with the users' requirement on the charging speed, some mobile terminals can accept the large current charging without monitoring the charging current. Meanwhile, some charging adaptors have been developed, via which constant charging with larger current can be performed. Although the charging time is reduced to some extent, the constant charging with larger current is easy to cause safety risk, for example, the cell can be overcharged if the charging adaptor still performs the large current charging when the cell is about to be fully charged or the electric quantity of the cell is comparatively sufficient before being charged by the charging adaptor.